Abstract

SUS301-EH is widely used as a material for exhaust system gaskets, however, at temperatures in excess of 400°C, it can not be used as gas-seal ability of the material declines due to its reduced hardness. The following methods were found to be effective in controlling the softening of stainless steel at high temperatures: (1) addition of N; (2) Stabilization of austenite structure; (3) addition of Mo. The addition of 0.5% N to austenitic stainless steel containing Mo has enabled the speed of softening at high temperatures to be significantly reduced, due to strain aging by solid N below 600°C and the combined effects of precipitation hardening and control of growth of recrystallized grains through the precipitation of fine Cr2N on the dislocations and the grain boundary above 600°C. A high-heat-resistant spring material has been developed which shows no reduction in hardness up to at 600°C, which is higher by 200°C or more compared to conventional materials. The application of this material to exhaust gaskets has enabled the achievement of excellent seal performance even in tightened sections in high-temperature environments of 400°C and above, which was problematic for conventional gasket materials.

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Author (organization or company)

• Takashi KATSURAI（Tochigi R&D Center）
• Tadao NISHIYAMA（Tochigi R&D Center）
• Shuji HAMANO（Daido Steel Co., Ltd.）

Publication Information

Article of Honda R&D Technical Review Vol.15 No.2 (167 - 174)

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